Hydraulic open hole well packer

ABSTRACT

A WELL PACKER FOR SEALING-OFF A WELL BORE, THE SEAL ELEMENT OF THE PACKER COMPRISING A PLURALITY OF ANNULAR SEGMENTS OF DEFORMABLE RESILIENT MATERIAL ARRANGED IN A STACKED RELATION FOR RADIAL EXPANSION IN RESPONSE TO ENDWISE COMPRESSION BY FLUID PRESSURE-ACTUATED MEANS, THE INDIVIDUAL SEGMENTS HAVING SPECIALLY SHAPED LIP ELEMENTS NESTABLE IN CORRESPONDINGLY   SHAPED RECESSES IN THE HEXT ADJACENT SEGMENTS AND INITIALLY SECURED THEREIN BY MEANS OF A LAYER OF ADHENSIVE MATERIAL WHEREBY TO OBVIATE ACCIDENTAL SETTING OF THE PACKER, THE ADHENSIVE LAYER BEING RELEASABLE IN RESPONSE TO THE ENDWISE COMPRESSION FOR SETTING THE PACKER.

United States Patent Inventor Cicero C. Brown 5429 Stnrbridge Drive, Houston, Tex. 77027 Appl. No. 27,024

Filed Apr. 9, 1970 Patented June 28, 1971 nvnn uug QPENl lOLE WELL PACKER 6 Claims, 3 Drawing Figs.

US. Cl. 166/187 Int. (:1. 5211133/12 Fieldoiseareh... 166/187, 196; 277/1 168 References Cited UNITED STATES PATENTS 7/1960 Smith 166/187 3,215,205 11/1965 Sizer ..1- 166/187 3,283,820 11/1966 Tausch 166/187 3,342,268 9/1967 Brown 166/196 Primary Examiner -James A Leppink AltomeyR. Werlin ABSTRACT: A well packer for sealing-off a well bore, the Seal element of the packer comprising a plurality of annular segments of deformable resilient material arranged in a stacked relation for radial expansion in response to endwise compression by fluid pressure-actuated means, the individual segments having specially shaped lip elements nestable in correspondingly shaped recesses in the next adjacent segments and initially secured therein by means of a layer of adhesive material whereby to obviate accidental setting of the packer, the adhesive layer being releasable in response to the endwise compression for setting the packer.

PATENTED JUN28 IHYI SHEET 2 0F 2 A TTO/PNE HYDRAULIQQPEN QLEWELL PACLC In connection with the drilling, cementing and completion of wells such as oil and gas wells, it is frequently necessary to set packers in the open uncased bore holes. Such packers ordinarily require seal elements which are expansible to substantially large diameters to enable them to accommodate to the frequently rough and pitted wall defined by the earth formations intersected by the bore hole.

In some known forms of such open hole packers, the sealing element is made up of a plurality of rings mounted in a stacked relation about a tubular body and constructed from a suitable deformable, generally resilientmaterial, such as natural or synthetic rubber, or other plastic composition. The seal element is arranged for radial expansion to the desired extent by endwise compression which is exerted by fluid pressureoperated means. A packer of this general type is illustrated in one ofmy earlier applications, Ser. No. 279,583, filedMay I0, 1963, now abandoned.

One of the difficulties with the earlier design of open hole packers such as describedabove, is that during running of the packer, the peripheral lips of the rings forming the seal element tend to flare outwardly under opposing forces exerted by fluid in the well bore through which the packer is lowered and this force may be sufficiently great to cause the seal elements to catch on projections on the rock formations defining the surrounding well wall, particularly where it is rough, and cause premature setting of the packer. If not causing premature setting, the rough rock wall surfaces may cause sufficient tearing of the ring lips and the rings themselves to greatly damage or reduce the sealing effectiveness of the seal element.

To obviate the deficiencies of the earlier designs while retaining the advantages of the multiple-ring construction, which is particularly useful for open hole sealing, the present invention contemplates providing the adjacent ring segments of the seal element with a specialized shape of lip and a cooperating recess to receive the same such that the seal element as a whole, in its retracted condition, will present a flush, substantially uninterrupted cylindrical exterior surface. Moreover, the ring segments are provided with a layer of adhesive material designed to initially strongly secure the lips of the ring segments in their related recesses, to thereby prevent the undesired flaring of the lips as occur in earlier designs both to obviate premature setting of the packer and reduce the danger of tearing of therings on the well bore surfaces. The adhesive material, however, is releasable in response to endwise pressure applied to the sealing element by fluid pressure means when setting-of the packer is desired.

In accordance with the illustrative embodiment of this in-. vention, the packer includes a tubular body supportinga seal element which comprises a central expander ringsegment, and a plurality of downwardlyfacing, cup-shaped ring segments, seated on the upper end of the expander segment and a plurality of upwardly facing cup-shaped ring segments seated against the lower end of the expander segment. Each cupshaped ring segment has an annular cylindrical lip extending longitudinally from the outer periphery thereof parallel to the axis of the segment, and a correspondingly shaped recess in its outer periphery at the end of the segment opposite the lip. Thus, when the rings are stacked the lip on one ring will be received in close-fitting relation in the recess of the next adjacent ring. The central expander ring is provided with oppositely conically tapered ends to receive the oppositely facing cup-shaped ring segment and both ends of the expander ring are provided with recesses adapted to receive the lips of the next adjacent ring segments.

A layer of adhesive material is interposed between the engaged surfaces of each lip and its related recess to strongly secure the lips in their retracted relation until the force of endwise compression is applied to expand the seal element which will break the grip of the adhesive to allow the desired expan- The upper end of the packer body carries a fixed abutment member engaging the upper end of the seal element. The

lower end of the seal element is connected to a movable abutment member slidably mounted about the body and secured to an extension sleeve which defines a cylinder about the packer body. The cylinder encloses an annular piston slidably disposed about the packer body. The piston, in response to fluid pressure introduced into the cylinder, will apply endwise compression to the sealing element to expand the latterand set the packer. The packer includes adjustment means connecting the extension sleeve to the packer body to urge the ring segments snugly together when initially assembled on the packer body.

Other and more specific objects and advantages of this invention will become more readily apparent from the following detailed description when read inconjunction with the accompanying drawing which illustrates auseful embodiment in accordance with this invention.

In the Drawing:

FIG. 1 is a longitudinal, quarter sectional view of the packer showing the seal elements in their retracted position;

FIG. 2 is a view similar to'FIG. 1 showing the packer in its actuated or expanded condition; and

FIG. 3 is an enlarged partially sectional view of the seal element of the packer to illustrate the details thereof.

Referring to the drawing, the packer comprises a tubular body 10, having externally threaded pins 11 and 12 at its upper and lower ends respectively for connecting the packer into a string of pipe P, upper pin member 11 being shown connected to pipe P by means of a collar 13. The latter is externally threaded at 14 to be connected into an abutment ring 15 constructed of metal, which is thereby fixedly secured to the upper end of the packer body. Mounted about the packer body is-the seal element, designated generally by the numeral 16, which comprises a central annular expander segment 17 having upper and lower conically inwardly tapering end portions 18 and 19 respectively. A plurality of annular downwardly facing cup-shaped ring segments '20 are nested'or stacked one inside the other with the lowermost one of the upper group seated over the upper end 18 of expander segment 17. A similar group of identical 'ring segments 20, but facing upwardly, are disposed to seat over the lower end portion 19 of the expander segment.

Each of the ring segments is provided at one end with a peripheral lip 21 which extends longitudinally parallel to the centralaxis of the ring and is of a generally cylindrical shape terminating in a flat end face 22. At its opposite end each ring segment is provided on its outer periphery with an annular recess 23 complimentary in shape to lip 21 so that when'the ring segments are stacked one on the other, lip 21 of one segment will be recessed snugly in recess 23 of the next adjacent segment. Upper and lower end portions 18 and 19 of expander ring segment 17 are provided with recesses 23 to receive the lips 21 of the ring segments next adjacent both its upper and lower ends.

All of the ring segments will be constructed of any suitable deformable, resilient material such as a natural or synthetic rubber or resilient composition thereof and other well known plastic materials used for manufacture of the sealing elements of the type described. As best seen in FIG. 3, a layer of a suitable glue or adhesive material 24 is applied between the inner surface of each lip 21 and the opposed surface of the related recess 23 as well as between end face 22 and the bottom of recess 23. This adhesive may be any well-known composition which has the properties of fast setting, high strength and ability to cure without heat or mixing. A suitable material of this character is sold under the trade name Eastman 910 manufactured by Eastman Chemical Products, Inc., Chemical Division, Kingsport, Tennessee, which contains Methyl-2- Cyanoacrylate resin. This type of adhesive will effectively secure the engaged lip and recess portions of the ring'segments to prevent flaring of' the lips during running of the packer under all normal conditions but which, when the seal assembly is subjected to endwise compression for purposes of seating the packer as will he described hereinafter, will permit the adhesive grip of this material to be broken allowing the ring segments of the seal element to expand radially as desired.

Abutment ring is provided with a peripheral, longitudinally downwardly extending flange 25 which overlaps the upper end of the uppermost one of the ring segments and encloses a split metal collet 26 which reinforces the upper end of the ring segment and forms a part of the abutment engaging the upper end of the seal element as a whole, the split fingers of the collet permitting'radial expansion of the rings as seen particularly in FIG. 2. A similar abutment ring 27 provided with a longitudinally upwardly extending peripheral flange 28 engages the lower end of the lowermost one of ring segments 20 and likewise encloses a split collet 29. Abutment ring 27 is slidable on body 10 and has secured about its lower end an extension sleeve 30 concentrically spaced from body 10 to define a cylinder 31. The upper end of cylinder 31 is closed by a head ring 32 slidable about body 10. The lower end of cylinder 31 is closed by means of a cylinder head 33 which is rigidly secured to the exterior of body 10 but is slidable with respect to sleeve 30. Suitable packing rings 34 and 35 are provided between both sides of head ring 32 and body 10 and sleeve 30 while packing rings 36 form a seal between cylinder head 32 and body 10. One or more ports 37 are provided through the wall of body 10 between head ring 32 and cylinder head 33.

An adjustment nut 38 is threadedly secured to a threaded ring 39 mounted adjacent the lower end of body 10. The shank 40 of nut 38 is releasably secured to the lower end of sleeve 30 by means ofa shear pin 41 which when broken will allow relative longitudinal movement of the sleeve member with respect to body 10.

The bore of lower abutment ring 27 is downwardly and outwardly tapered to provide the conically tapered surface 42 in which is mounted a plurality (one shown) of correspondingly tapered wedge slips 43 having downwardly facing buttress teeth 44 on their inner faces. These slips serve to hold the seal element in its expanded position when the lower abutment member has been moved upwardly in effective endwise compression of the seal element. A port 45 is provided through the wall of sleeve 30 just above the inner end of shank 40 of the adjusting nut to permit drainage of any fluid trapped between cylinder head 33 and the adjusting nut during operation of the device.

The adjusting nut is used in connection with the assembly of the segments of the seal element on body 10, particularly where it is necessary to bring all of the nested ring segments into close fitting relation to assure close contact of the adhesive. This is accomplished by screwing nut 38 inwardly to tighten the assembly which can be loosened by screwing the nut outwardly. The inner end of shear pin 41 rides in an annular groove 46 in ring 39 so that the nut can be turned freely relative to sleeve 30.

When the ring segments are all assembled on body 10, and the adhesive material interposed between lips 21 and recesses 23, the overall assemblage of the seal element will present a flush, substantially uninterrupted cylindrical surface which will have no crevices between the ring segments or irregular protrusions which might otherwise interfere with the running of the packer in an open well bore or through whatever liquid may be present in the bore.

When the packer has been lowered on pipe string P to the desired location in well bore W a plug (not shown) will be dropped through the bore of the pipe string and body 10 to a seat (not shown) but located in the pipe string below body 10, a generally conventional arrangement, in order to close off the bore of the pipe string and body 10 above the plug. Thereafter fluid is pumped through the bore of the pipe string into the body 10 and its pressure increased so that the resulting pressure applied through ports 37 is exerted upwardly on head ring 32 and thence transmitted to lower abutment ring 27, these being slidable on body 10. With cylinder 3'1 closed off by cylinder head 33 the upward force exerted against the lower end of the seal element through lower abutment ring 27 will, after breaking shear pin 41, compress the seal element against upper abutment ring 15. The resulting endwise or axial compression will serve to break the bonds formed by adhesive 24 between the several ring segments and allow the ring segments under the endwise compression to expand radially, the segments moving over one another until they are in compressive engagement with the wall of well bore W, as best seen in FIG. 2. When the packer has thus been set, slips 43 will act through teeth 44 to hold the packer in its expanded position and thereby enable maintenance of a fluid tight seal between body 10 and the wall of the well bore.

It will be understood that various changes and modifications may be made in the details of the illustrative embodiment within the scope of the appended claims but without departing from the spirit of this invention.

lclaim:

l. A well packer comprising:

a. a tubular body; and

b. an annular seal element mounted about the body, said seal element comprising:

i. a central expander segment having upwardly and downwardly tapering upper and lower ends respectivey;

ii. a plurality of downwardly opening cup-shaped segments superimposed on each other with the lowermost one being seated over said upper end of said central segment;

iii. a plurality of upwardly opening cup-shaped segments superimposed on each other with the uppermost one being seated over said lower end of said central segment;

iv. each of said cup-shaped segments having a longitudinally extending, cylindrical peripheral lip receivable in a correspondingly shaped peripheral recess in the next adjacent segment so that when all of the segments are assembled the exterior of the seal element will present a flush substantially uninterrupted surface; a layer of adhesive between the contacting surfaces of said lips and said recesses adapted to initially hold said lips in their contracted positions in said recesses and releasable in response to endwise compression exerted on the seal element in effecting radial expansion of said segments; and

c. means mounted on the body for applying endwise compression to said seal element.

2. A well packer according to claim 1 wherein said means for applying endwise compression is a fluid pressure-operated means.

3. A well packer according to claim 1 wherein said means for applying endwise compression to said seal element comprises:

a. a first abutment member fixedly mounted on said body in engagement with one end of said seal element;

b. a second abutment member slidably mounted on said body in engagement with the opposite end of said seal element; and

c. fluid pressure-operated means mounted on the body arranged to urge said second abutment member toward said first abutment member.

4. A well packer according to claim 3 wherein said fluid pressure-operated means comprises:

a. a sleeve member concentrically disposed about said body and secured to said second abutment member for axial movement therewith; b. axially spaced seal means between the body and said sleeve members to define a pressure cylinder therebetween; and

c. port means communicating the bore of said body with the interior of said cylinder.

5. A well packer according to claim 3 including:

a. a sleeve member concentrically disposed about said body and secured to said second abutment member for axial movement therewith; and

b. an adjustmem means operably arranged between said sleeve member and said body for moving said sleeve member axially relative to said body.

6. A well packer according to claim 5 wherein said adjust- 

